REPORT OF COMMISSIONERS OF INLAND FISHERIES. 109 



These results, then, indicate that there is a certain period preceding 

 an ecdysis in which if a thoracic appendage is removed, the Hmb will 

 not begin to regenerate before the following moult. Whether this 

 limit approaches any regular per cent, of the whole interval between 

 two moults, it would require a larger number of comparative obser- 

 vations to determine. 



The second question to be considered is whether there is any adap- 

 tation of the regenerative or moulting processes favorable to the early 

 restoration of a lost appendage. 



In the attempt to ascertain whether the moulting process is de- 

 layed, or, what is the same thing, whether the interval between 

 moults is lengthened by the presence of regenerating structures, it 

 is necessary to know first the average length of the moulting period 

 of a normal lobster at a given stage. If this were known, then the 

 question might be answered by observing whether that period is 

 lengthened in a lobster with structures regenerating. 



During the present summer Prof. A. D. Mead has collected data 

 and made observations upon the moulting periods of young lobsters 

 in which the stages are known. A tabulated form of Prof. Mead's 

 results may be found in this report, page 40. This table shows that 

 the average duration of the fifth stage for the normal lobsters was 

 9^ days; and of the sixth stage 12.7 days. 



For these two periods, then, we have now a basis for comparison 

 with the results obtained from experiments on mutilated lobsters. 

 The following table gives the moulting periods of fourteen fourth, 

 fifth, and sixth stage lobsters, in which one or more appendages were 

 in the process of regeneration: 



